The email address you supply must be unique. This is a WordPress requirement which we are using for security management (each registration results in a WordPress user on the system, which is allowed to manage his/her own details). This is also a common feature of most social media sites.
We have had a few enquiries relating from Tower Captains who wish to register on behalf of their pupils. Ideally, you should ask a parent/guardian to register on their child’s behalf. You should NOT register your pupil on their behalf, unless you have express permission from the parent/guardian – and ideally you would need to use their own email address.
This may still result in a parent requiring several children to be registered. We suggest that (for example) a gmail account is registered in each of the children’s names (it is going to be useful in the future if not immediately). Once created, simply enable forwarding to the relevant parent account.